1,072 research outputs found

    Developing critical reading, thinking and discussion skills among students at a Masters level using virtual learning environment

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    Students entering higher education at Masters level often struggle to develop skills of critical reading, discussion and analysis. That lack of skills often affects the quality of students’ written coursework, even if such work shows an extensive knowledge and understanding of the topic. Academic literature suggests that skills, including cognitive ones, are best developed by repetition. However, even though graduate programs usually offer students lectures and tutorials on critical thinking and analysis, they often lack teaching capacity to repeat those activities until a desired level of students’ skills is achieved. This paper aims to introduce a teaching activity that would allow a repetition essential for developing the desired skills, which would at the same time require minimum teaching resources to support the activity. The proposed skill repetition activity took a form of generic Quizzes with automotive feedback embedded in Virtual Learning Environment. The students were asked to evaluate several academic articles by answering generic Quiz questions on the following 6 themes: purpose, literature review, objectives, research methods, findings and conclusions of an article. The students received an instantaneous feedback after submitting their answers by being able to see the answers given by their tutors on the same paper. The results were later discussed in class. The effectiveness of the developed on-line Quizzes were tested at two modules: one core and one elective, which have the same assessment type; summative assignment consisting of 2500 words report. The MSc course in question is delivered by face-to-face teaching at two locations: at one location it is delivered via traditional classroom based teaching, on other — via blended learning. Both cohorts were included. The success of the proposed approach was judged based on the following criteria: - students' performance in their first written submission at the end of the semester compared with performance on the same submission showed in the previous year; - improvement of individual students’ skills, based on the improvement of their answers in each successive quiz as compared to tutors' answers; - a feedback about those quizzes received from the students; - amount of teaching resources required to support the quizzes. So far we have only marks for student's submission for one module, however, the paper will report findings for both modules. The findings revealed that: - in comparison to the previous year, students’ average mark in their first written submission has increased from 'good' to ‘very good’; the spread of marks within the cohort was narrower; the spread of marks between a first and a second supervisor was substantially reduced. - the results from successive quizzes showed a gradual improvement in individual student’s critical thinking and analysis skills. - feedback from the students revealed that they found the quizzes activities helpful in developing their skills of critical reading of published literature. - the amount of teaching resources needed for a continuous support of the quizzes was reduced to a minimum. The study revealed a value of a proposed activity in developing students' skills of critical reading, discussion and analysis. Some limitations were also revealed, such as a need for substantial initial teaching resources. It would also be beneficial to replicate a study on a bigger cohort

    The law of action and reaction for the effective force in a nonequilibrium colloidal system

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    We study a nonequilibrium Langevin many-body system containing two 'test' particles and many 'background' particles. The test particles are spatially confined by a harmonic potential, and the background particles are driven by an external driving force. Employing numerical simulations of the model, we formulate an effective description of the two test particles in a nonequilibrium steady state. In particular, we investigate several different definitions of the effective force acting between the test particles. We find that the law of action and reaction does not hold for the total mechanical force exerted by the background particles, but that it does hold for the thermodynamic force defined operationally on the basis of an idea used to extend the first law of thermodynamics to nonequilibrium steady states.Comment: 13 page

    A dynamical theory of homogeneous nucleation for colloids and macromolecules

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    Homogeneous nucleation is formulated within the context of fluctuating hydrodynamics. It is shown that for a colloidal or macromolecular system in the strong damping limit the most likely path for nucleation can be determined by gradient descent in density space governed by a nontrivial metric fixed by the dynamics. The theory provides a justification and extension of more heuristic equilibrium approaches based solely on the free energy. It is illustrated by application to liquid-vapor nucleation where it is shown that, in contrast to most free energy-based studies, the smallest clusters correspond to long wavelength, small amplitude perturbations.Comment: final version; 4 pages, 2 figure

    Dietary fish oil preserves cardiac function in the hypertrophied rat heart

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    Regular fish or fish oil intake is associated with a low incidence of heart failure clinically, and fish oil-induced reduction in cardiac remodelling seen in hypertrophy models may contribute. We investigated whether improved cardiac energy efficiency in non-hypertrophied hearts translates into attenuation of cardiac dysfunction in hypertrophied hearts. Male Wistar rats (n 33) at 8 weeks of age were sham-operated or subjected to abdominal aortic stenosis to produce pressure-overload cardiac hypertrophy. Starting 3 weeks post-operatively to follow initiation of hypertrophy, rats were fed a diet containing 10% olive oil (control) or 5% fish oil (ROPUFA® 30 (17% EPA, 10% DHA))+5% olive oil (FO diet). At 15 weeks post-operatively, ventricular haemodynamics and oxygen consumption were evaluated in the blood-perfused, isolated working heart. Resting and maximally stimulated cardiac output and external work were >60% depressed in hypertrophied control hearts but this was prevented by FO feeding, without attenuating hypertrophy. Cardiac energy efficiency was lower in hypertrophy, but greater in FO hearts for any given cardiac mass. Coronary blood flow, restricted in hypertrophied control hearts, increased with increasing work in hypertrophied FO hearts, revealing a significant coronary vasodilator reserve. Pronounced cardiac dysfunction in hypertrophied hearts across low and high workloads, indicative of heart failure, was attenuated by FO feeding in association with membrane incorporation of n-3 PUFA, principally DHA. Dietary fish oil may offer a new approach to balancing the high oxygen demand and haemodynamic requirements of the failing hypertrophied heart independently of attenuating hypertroph

    Extended Clausius Relation and Entropy for Nonequilibrium Steady States in Heat Conducting Quantum Systems

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    Recently, in their attempt to construct steady state thermodynamics (SST), Komatsu, Nakagwa, Sasa, and Tasaki found an extension of the Clausius relation to nonequilibrium steady states in classical stochastic processes. Here we derive a quantum mechanical version of the extended Clausius relation. We consider a small system of interest attached to large systems which play the role of heat baths. By only using the genuine quantum dynamics, we realize a heat conducting nonequilibrium steady state in the small system. We study the response of the steady state when the parameters of the system are changed abruptly, and show that the extended Clausius relation, in which "heat" is replaced by the "excess heat", is valid when the temperature difference is small. Moreover we show that the entropy that appears in the relation is similar to von Neumann entropy but has an extra symmetrization with respect to time-reversal. We believe that the present work opens a new possibility in the study of nonequilibrium phenomena in quantum systems, and also confirms the robustness of the approach by Komtatsu et al.Comment: 19 pages, 2 figure

    A note on the violation of the Einstein relation in a driven moderately dense granular gas

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    The Einstein relation for a driven moderately dense granular gas in dd-dimensions is analyzed in the context of the Enskog kinetic equation. The Enskog equation neglects velocity correlations but retains spatial correlations arising from volume exclusion effects. As expected, there is a breakdown of the Einstein relation ϵ=D/(T0μ)1\epsilon=D/(T_0\mu)\neq 1 relating diffusion DD and mobility μ\mu, T0T_0 being the temperature of the impurity. The kinetic theory results also show that the violation of the Einstein relation is only due to the strong non-Maxwellian behavior of the reference state of the impurity particles. The deviation of ϵ\epsilon from unity becomes more significant as the solid volume fraction and the inelasticity increase, especially when the system is driven by the action of a Gaussian thermostat. This conclusion qualitatively agrees with some recent simulations of dense gases [Puglisi {\em et al.}, 2007 {\em J. Stat. Mech.} P08016], although the deviations observed in computer simulations are more important than those obtained here from the Enskog kinetic theory. Possible reasons for the quantitative discrepancies between theory and simulations are discussed.Comment: 6 figure

    Representation of nonequilibrium steady states in large mechanical systems

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    Recently a novel concise representation of the probability distribution of heat conducting nonequilibrium steady states was derived. The representation is valid to the second order in the ``degree of nonequilibrium'', and has a very suggestive form where the effective Hamiltonian is determined by the excess entropy production. Here we extend the representation to a wide class of nonequilibrium steady states realized in classical mechanical systems where baths (reservoirs) are also defined in terms of deterministic mechanics. The present extension covers such nonequilibrium steady states with a heat conduction, with particle flow (maintained either by external field or by particle reservoirs), and under an oscillating external field. We also simplify the derivation and discuss the corresponding representation to the full order.Comment: 27 pages, 3 figure

    Renormalization group study of the conductances of interacting quantum wire systems with different geometries

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    We examine the effect of interactions between the electrons on the conductances of some systems of quantum wires with different geometries. The systems include a wire with a stub in the middle, a wire containing a ring which can enclose a magnetic flux, and a system of four wires which are connected in the middle through a fifth wire. Each of the wires is taken to be a weakly interacting Tomonaga-Luttinger liquid, and scattering matrices are introduced at all the junctions. Using a renormalization group method developed recently for studying the flow of scattering matrices for interacting systems in one dimension, we compute the conductances of these systems as functions of the temperature and the wire lengths. We present results for all three regimes of interest, namely, high, intermediate and low temperature. These correspond respectively to the thermal coherence length being smaller than, comparable to and larger than the smallest wire length in the different systems, i.e., the length of the stub or each arm of the ring or the fifth wire. The renormalization group procedure and the formulae used to compute the conductances are different in the three regimes. We present a phenomenologically motivated formalism for studying the conductances in the intermediate regime where there is only partial coherence. At low temperatures, we study the line shapes of the conductances versus the electron energy near some of the resonances; the widths of the resonances go to zero with decreasing temperature. Our results show that the conductances of various systems of experimental interest depend on the temperature and lengths in a non-trivial way when interactions are taken into account.Comment: Revtex, 17 pages including 15 figure

    Transport coefficients for dense hard-disk systems

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    A study of the transport coefficients of a system of elastic hard disks, based on the use of Helfand-Einstein expressions is reported. The self-diffusion, the viscosity, and the heat conductivity are examined with averaging techniques especially appropriate for the use in event-driven molecular dynamics algorithms with periodic boundary conditions. The density and size dependence of the results is analyzed, and comparison with the predictions from Enskog's theory is carried out. In particular, the behavior of the transport coefficients in the vicinity of the fluid-solid transition is investigated and a striking power law divergence of the viscosity in this region is obtained, while all other examined transport coefficients show a drop in that density range.Comment: submitted to PR

    Mott localization in the correlated superconductor Cs3C60 resulting from the molecular Jahn-Teller effect

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    Cs3C60 is a correlated superconductor under pressure, but an insulator under ambient conditions. The mechanism causing this insulating behavior is the combination of Mott localization and the dynamic Jahn-Teller effect. We show evidence from infrared spectroscopy for the dynamic Jahn-Teller distortion. The continuous change with temperature of the splitting of infrared lines is typical Jahn-Teller behavior, reflecting the change in population of solid-state conformers. We conclude that the electronic and magnetic solid-state properties of the insulating state are controlled by molecular phenomena. We estimate the time scale of the dynamic Jahn-Teller effect to be above 10^(-11) s and the energy difference between the conformers less than 20 cm-1
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